I have the Horizon 7700
What do I love about it? Everything. It has an 11 inch harp opening, it has the Accufeed system, it has tons of great stitches, it is really easy to use. It has a low bobbin sensor. It has the ability to clip your thread right at the fabric, right after it ties the knot. Gotta love that. It is really fun. I chose it over the 6600 because of the harp size and the free arm.
What I don't love about it? Is that I don't have enough time recently to play with it.
I paid a total of $2100 for it, including the special table, acrylic insert and acrylic table extender and tax. He through in a bunch of bobbins, some special feet and a great pamphlet on the anatomy of a needle.
This is my second Janome (third, if you count my New Home) and I can't imagine having any other brand.